Spam and Virus Protection

PolarisMail uses a layered approach when dealing with Spam and Viruses, each level rejecting or quarantining the incoming message. Except for the Whitelist / Blacklist filters there are no other filters being applied for e-mails sent between PolarisMail e-mail accounts; this allows internal e-mail to flow freely

1. All incoming connections are first checked against 3 high accuracy RBL servers. All IP addresses matching an RBL record are rejected at this level

2. All incoming messages display a From address that contains a domain. PolarisMail verifies if the sending domain contains valid MX records ( all domains sending e-mail should have valid MX records ). If no MX records are found, the e-mail is rejected with a hard smtp error

3. The system next verifies the recipient for which the e-mail is destined. If the recipient does not exist on the PolarisMail servers and no catch-all is defined, the e-mail is rejected with a hard smtp error

4. If the sender and recipient are valid, the system verifies the Whitelist / Blacklist filters looking for a match. If a match is found in the Whitelist, the e-mail is properly flagged and sent for delivery. If a match is found in the Blacklist the e-mail is rejected with a hard smtp error

5. At this level the message is scanned by ClamAV for potential viruses. If a virus is found and there is no pass-through flag from the Whitelist filter, the message is rejected with a hard smtp error.

6. The message is now scanned by DSPAM in order to establish its potential as a Spam message. Depending on the resulting score and on the spam preferences, the message will be either rejected, quarantined or delivered.

Each Administrator has the option for creating special Retraining e-mail addresses where users may forward e-mails that were incorrectly labeled as Spam or Spam e-mails that passed through. This way the system will learn of the mistake it made and won't repeat it in the future.